析湿工况下平直开缝翅片传热传质特性的数值研究

doi:10.11949/0438-1157.20221440

摘要/Abstract

摘要：

针对现有冷凝模型计算中未考虑对流传质对传质通量的影响，利用Fluent软件中的UDF建立了新的对流冷凝传热模型和基于场协同理论的传热传质特性分析方法。使用新的冷凝模型和分析方法对除湿条件下，入口参数、翅片结构、开缝位置对平直开缝翅片换热器湿空气侧的流动、传热和传质特性的影响进行了研究。结果表明：考虑对流传质的冷凝模型准确度得到提升；传热量、冷凝量随翅片表面开缝高度的增加先减小后增加；上游开缝翅片管的传热量、冷凝量均低于下游开缝翅片管，利用建立的分析方法发现，相同边界条件下，下游开缝翅片的传热场协同角α_m、传质场协同角β_m均小于上游开缝翅片，表明下游开缝翅片的速度场、温度梯度场和浓度梯度场的协同性更优，传热传质能力更强。

关键词: 平直开缝翅片, 传热传质, 除湿条件, 冷凝传热模型, 场协同理论

Abstract:

In this paper, a new convection condensation heat transfer model and an analysis method of heat and mass transfer characteristics based on field synergy theory are established by using UDF in fluent, aiming at the lack of consideration of the influence on mass transfer in the calculation of mass transfer flux of existing condensation models. The flow, heat transfer and mass transfer characteristics of wet air side of straight slotted fin heat exchanger under dehumidification conditions are studied by using new condensation model and analysis method. The results show that the accuracy of condensation model considering convective mass transfer is improved. The amount of heat transfer and condensation decreases first and then increases with the increase of the slit height on the fin surface. The heat transfer and condensation of the upstream slotted fin tube are lower than those of the downstream slotted fin tube. Using the established analysis method, it is found that under the same boundary conditions, the synergistic angle α_m and β_m of the downstream slotted fin are smaller than those of the upstream slotted fin, which indicates that the downstream slotted fin has better synergy between the velocity field and the temperature gradient field, the velocity field and the concentration gradient field, and the heat and mass transfer capacity is stronger.

Key words: straight slotted fins, heat and mass transfer, dehumidification conditions, condensation heat transfer model, field synergy theory

中图分类号:

TK 124

何洋, 高森虎, 吴青云, 张明理, 龙涛, 牛佩, 高景辉, 孟颖琪. 析湿工况下平直开缝翅片传热传质特性的数值研究[J]. 化工学报, 2023, 74(3): 1073-1081.

Yang HE, Senhu GAO, Qingyun WU, Mingli ZHANG, Tao LONG, Pei NIU, Jinghui GAO, Yingqi MENG. Numerical study on heat and mass transfer characteristics of straight slotted fins under wet conditions[J]. CIESC Journal, 2023, 74(3): 1073-1081.

图/表 13

图1 平直开缝翅片和平直翅片结构示意图

Fig.1 Straight slotted fin and straight fin structure diagram

表1 翅片管换热器主要结构参数

Table 1 Main structural parameters of finned tube heat exchanger

参数	平直开缝翅片	平直翅片
管外径 d/mm	7.2	7.2
管壁厚 δ₁/mm	0.3	0.3
翅片间距 S/mm	1.5	1.5
翅片厚度 δ₂/mm	0.105	0.105
纵向管间距 P₁/mm	12.7	12.7
横向管间距 P₂/mm	14.4	14.4
开缝尺寸/(mm×mm)	4×1	—

图2 湿空气横掠平板

Fig.2 Wet air swept flat plate

图3 平直开缝翅片和平直翅片网格图

Fig.3 Straight slotted fin and straight fin grid

图4 边界条件设定

Fig.4 Boundary condition setting

图5 翅片通道中流体的速度和压力分布

Fig.5 Velocity and pressure distribution

图6 翅片通道中流体的温度和浓度分布

Fig.6 Temperature and concentration distribution

图7 入口速度、水蒸气体积分数对总传热量和冷凝量的影响

Fig.7 Effect of inlet velocity and water vapor volume fraction on total heat transfer and condensation

图8 开缝高度对总传热量和冷凝量的影响

Fig.8 Effect of slit height on total heat transfer and condensation

图9 开缝高度对协同角αm、βm的影响

Fig.9 Effect of slit height on synergistic angle αm and βm

图10 上游开缝翅片管和下游开缝翅片管

Fig.10 Upstream slotted finned tube and downstream slotted finned tube

图11 开缝位置对总传热量、冷凝量的影响

Fig.11 Effect of slit position on total heat transfer and condensation

图12 开缝位置对协同角αm、βm的影响

Fig.12 Effect of slit position on synergistic angle αm and βm

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